Re: for_each_online_cpu broken ?

Andi Kleen
2005-12-08T06:30:22Z

On Thu, Dec 08, 2005 at 01:28:44AM -0500, Dave Jones wrote:
> On Thu, Dec 08, 2005 at 04:22:05PM +1000, Nigel Cunningham wrote:
>
> > > Yep, I noticed it offers a maximum of 6 cpus on my way.
> > > As a sidenote, seems kinda funny (and wasteful maybe?), doing this
> > > on a lot of hardware that isn't hotplug capable. (Whilst I could
> > > disable cpu hotplug in my local build, this isn't an answer for
> > > a generic distro kernel).
> >
> > Both suspend to disk (and suspend to ram?) implementations now depend on
> > hotplug_cpu to enable extra cpus, so there is at least one reason for
> > them to want hotplug support in a generic kernel.
>
> You mean suspend -> plug in a new cpu -> resume transitions ?
> That sounds *terrifying*.

No, they unplug all non BP CPUs before suspending.
It obviously doesn't require additional CPUs though.

-Andi